1. Field
The present disclosure relates to a genetically engineered yeast cell having increased NADPH production, a method of increasing a NADPH level in a yeast cell, a method of preparing the yeast cell, and a method of producing lactate using the yeast cell.
2. Description of the Related Art
Lactate is an organic acid widely used in a variety of industrial fields, including food, pharmaceutical, chemical, and electronic industries. Lactate is a colorless, odorless, water-soluble, low-volatile material. Lactate is also not toxic to the human body and is used as a flavoring agent, a sour taste agent, a preserving agent, or the like. Additionally, lactate is used as a source of polylactic acid (PLA) that is an environmentally friendly, biodegradable plastic known as an alternate polymeric material. Technically, PLA is a polyester-based resin obtained by ring-opening polymerization of a dimer lactide for polymerization. PLA may be variously processed into a film, a sheet, a fiber, an injection, etc. Thus, demands for PLA as a bioplastic have recently increased to broadly replace existing general petrochemical plastics, such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), or polystyrene (PS). In addition, lactate includes both a hydroxyl group and a carboxyl group and thus is highly reactive. Accordingly, lactate is easily converted into an industrially important compound, such as lactate ester, acetaldehyde, or propyleneglycol and thus has received attention as an alternative chemical material of the next generation for use in the chemical industry.
Currently, lactate is produced by an industrially petrochemical synthesis process and a biotechnological fermentation process. The petrochemical synthesis process is performed by oxidizing ethylene derived from crude oil, preparing lactonitrile through addition of hydrogen cyanide after acetaldehyde, purifying by distillation, and hydrolyzing using hydrochloric acid or sulfuric acid. The biotechnological fermentation process is used to manufacture lactate from a reproducible carbon hydrate, such as starch, sucrose, maltose, glucose, fructose, or xylose, as a substrate. Therefore, a strain capable of efficiently producing lactate and a method of producing lactate using the strain are needed. To meet these needs, a method of producing lactate using a microorganism has been developed. However, homeostasis of microorganisms is an obstacle to mass-production of a single material. The present inventors have studied this problem, thereby completing the present invention.